As well known, sheet metal piles are driven by a pile driver at a construction site into the ground or the bottom of a body of water, such as a stream or bay, for example. The sheet metal piles normally are of a channel or Z-shape in cross section and adjacent piles have interlocked side edges to prevent separation of the driven piles thereby to provide a continuous wall. Adjacent side edges of adjacent piles interfit in an interlocking relation and an undriven pile is raised and vertically aligned with an adjacent driven pile for subsequent threading or stabbing of the side edges upon lowering of the undriven pile thereby forming the interlocking relation. Sheet piles when handled for being driven in an earth formation, particularly if the pile is formed of a non-metallic material or a relatively thin metal material such as aluminum, may become damaged from lifting or driving into the ground. Sheet piles or piling for certain uses such as sea walls, for example, may be formed of interlocking piling extruded from special vinyl formulations. Sheet piles formed of a rigid vinyl material are resistant to marine bores, rot, rust, galvanic corrosion, or highly acidic or alkaline soil conditions.
For interfitting or threading the lower end of an undriven pile onto the vertically aligned upper end of the driven pile, the undriven pile must be lifted to a height above the upper end of the driven pile for threading of the interfitting edges of the driven pile and the undriven pile. A pile threading device is normally utilized for accurate threading of the interfitting edges at the upper end of the driven pile and the pile threading device may be lifted by the undriven pile to the upper end of the driven pile for threading of the piles. After the lower end of the undriven pile clears the upper end of the driven pile, a workman at ground level actuates a laterally movable slide on the pile threading device to move the upper undriven pile laterally into a vertically aligned position with the subjacent side edge of the driven pile for threading the side edge of the undriven pile onto the side edge of the fixed driven pile. The accurate positioning and alignment of the side edges of the adjacent sheet piles for threading or stabbing eliminates the necessity of a workman being present adjacent the upper end of the driven pile thereby avoiding a possible safety hazard. It is important that the sheet piles be accurately aligned for registering of the interfitting side edges for threading so that a workman at a ground location below the raised undriven pile can easily move the undriven pile into accurate vertical alignment with the adjacent side edge of the driven pile.
The undriven pile is normally raised by an overhead crane of the like relative to the fixed driven pile until the lower end of the undriven pile clears the upper end of the driven pile. A threading device such as shown in U.S. Pat. No. 5,618,135 dated Apr. 8, 1997 may be lifted by the undriven pile for accurately threading the side edges of the driven pile and undriven pile. For lifting of the undriven pile, an opening is provided in the pile along its upper edge and a hook from an overhead crane is received within the opening for lifting the undriven pile to a position above the upper end of the adjacent driven pile. When the sheet piles are formed of a non-metallic material, failure of the non-metallic material adjacent the opening may occur especially if the piles are of a relatively large weight and if the threading device are lifted by the undriven piles.
It is an object of the present device to provide an apparatus and method for lifting a sheet pile, particularly a non-metallic sheet pile, in a gripping action applied against opposed faces of the sheet pile.